Late last year, Medicaid expansion under the Affordable Care Act finally reached North Carolina, extending health security to an estimated 600,000 low-income residents. It brought the total of states that have embraced the policy to 40, leaving just 10 holdouts.

A Washington Post report added soon after, “North Carolina may be the last of the Medicaid expansion holdout states to reverse course for a while.” There was every reason to believe that was true.

But once in a while, as those who follow the issue closely know, surprises happen. The Clarion Ledger in Jackson, Mississippi, reported last week:

The state of Mississippi is one step closer to giving more than 210,000 residents access to healthcare via a Medicaid expansion bill. House Bill 1725 passed the House by a vote of 98-20, with no vocal opposition to the bill after it was introduced by Medicaid Committee Chair Missy McGee, R-Hattiesburg.

Yes, Mississippi is a reliably “red” state. And yes, Republicans continue to control all of the levers of power, including sizable majorities in the state House and state Senate.

But on this issue, after years in which the state’s health system has struggled and hospitals have struggled to keep their doors open, there’s newfound interest in progressive change.

Indeed, Jason White, Mississippi’s Republican state House speaker, is among the effort’s champions.

“As I have travelled across this state, visiting with business leaders, community officials, and ultimately voters, the most consistent message I hear is the demand to address the shortfalls in our health care accessibility, and availability in Mississippi,” White told reporters. “I found the desire to keep Mississippians in the workforce and out of our emergency rooms, transcending any political party and impacts all regions of our state. Our determination to improve access to health care is a vital piece of the economic puzzle as a healthy workforce supports a healthy economy.”

The bill that cleared the state House now heads to the state Senate, where there is reportedly a fair amount of interest in advancing the proposal.

There is, however, an important hurdle standing in the way of success: Republican Gov. Tate Reeves remains a fierce opponent of the idea, and even if the legislature were to pass Medicaid expansion, the governor would be able to veto it.

But the legislative math matters: In the state House, the legislation passed by a veto-proof majority. If there’s a comparable vote in the state Senate, Reeves’ opinion on the matter might very prove irrelevant.

As for how we arrived at this point, when the U.S. Supreme Court initially upheld the Affordable Care Act’s constitutionality, the court’s majority delivered some bad news to health care advocates: Medicaid expansion, the justices concluded, had to be optional, not mandatory under federal law.

In policy circles, many assumed this wouldn’t be too big a deal. After all, they thought, states would obviously want to do the right thing — not only for its low-income citizens, but also for its hospitals and state budgets. There are plenty of far-right ideologues and Republicans at the state level, the assumption held at the time, but they could do arithmetic. No state would choose to be so foolish as to voluntarily reject Medicaid expansion, right?

As things stand, 10 states have done exactly that — though there’s reason to believe that number might soon shrink. Watch this space.

This post updates our related earlier coverage.